Development of surface water monitoring networks is a critical factor in the assessment and protection

of water resources. This study focuses on evaluating the effectiveness of surface water quality monitoring

network and identify monitoring stations and water quality parameters which are important in assessing

annual variations of water quality in Gorgan-roud River, Golestan Province. Cluster Analysis (CA) was

used to monitor station grouping and Principal component analysis (PCA) and principal factor analysis

(PFA) techniques were used for Assessment of water quality monitoring stations. The analysis of water

quality data from nineteen water quality monitoring stations over a 12-year time period indicated that

three monitoring stations (Taghi-Abad, Shir-Abad, and Nodeh) were identified as less important in

explaining the annual variance of the water quality parameters. Also results revealed that total hardness

and EC are most important parameters at first component and in the second component, pH and HCO3

are appropriate for assessing variations of water quality parameters in the Gorgan-roud River.